The Corbyn Revolution Advances

The left consolidates control over Labour as the Tories fumble.

Intramural political feuds rarely warrant much attention, but developments within Britain’s Labour Party this week are a special case. The country’s main opposition that may be the next governing party extended its march to the left.

Party members on Monday elected three loyalists of left-wing leader Jeremy Corbyn to the party’s National Executive Committee, cementing Mr. Corbyn’s grip. One is Jon Lansman, a self-described “radical socialist” who founded Momentum, the group formed to support Mr. Corbyn against party moderates....